Deep-drawing steel



Patented Oct. 30, 1945 2,387,919 DEEP-DRAWING STEEL James E. Lose, Wilkinsburg, Pa.

No Drawing.

2 Claims.

This invention is concerned with nonaging steel, the object being to combine the advantages of rimmed steel insofar as its fine surface qualities are concerned with those of steel to which sufficient aluminum has been added to make it nonaging and which is therefore killed steel.

Steel intended for deep-drawing or working involving extreme deformations conventionally is a plain carbon steel of very low-carbon content, it seldom containing more than .10% carbon. Such a steel can be produced as either a, rimmed steel or as a steel that is killed by the use of aluminum. Also, it can be imparted nonaging characteristics by the proper use of aluminum, this requiring about 3 pounds of aluminum per ton of steel which is a greater amount than is necessary to produce a killed steel only.

When produced as a rimmed steel, it can be rolled into products having very good deepdrawing characteristics and possessing a very fine surface finish. However, it is necmsary to temper these products by cold working them so as to avoid subsequent stretcher strains known as Liiders lines, it then being necessary to draw or form the products very shortly after this tempering to avoid trouble from the a in phenomenon to which rimmed steel is subject.

n the other hand, when produced as a nonaging steel by the use of an appropriate amount of aluminum, the steel can be rolled into prodacts which can be kept for reasonable periods of time after being tempered by cold working, without trouble arising insofar as the evil of aging are concerned when the products are ultimately subjected to deep-drawing or other severe forming. However, this nonaging steel is a killed steel as has been explained, and a killed steel lacks the fine surface finish of a rimmed steel.

The fundamentals involved in the foregoing discussion of rimmed and nonaging low-carbon steels intended for use in connection with deepdrawing or forming operations, are so familiar to those skilled in the art as to obviate the need for detailed discussion.

The present invention is characterized in that low-carbon steel is poured into an ingot mold, this steel being oxidized to such an extent that it actively eflervesces in the mold. In other words, it may be a plain carbon rimming steel. This steel is permitted to eilervesce or rim in the mold until a skin solidifies that is or appreciable thickness, the thickness of the skin depending on the characteristics desired of This skin has all the characteristics of the skin the ultimate product. 4

, Application January 7, 1942, Serial No. 425,941

of an ordinary rimmed steel ingot, it consisting of very clean low-carbon steel.

At this point, instead of permitting the core of the ingot to solidify in the manner which would be characteristic of such an ingot, an excess of killing agent is introduced into the steel so that the core will subsequently exhibit nonaging properties. The killing agent removes oxygen from the steel, and an incident of this treatment is that the core solidifies as a killed steel, with deep piping.

The nonaging core should by way of example, be treated with about 3 lbs. of aluminum per ton of steel. This is preferably introduced, if it is a bottom-pouring operation, by adding further steel through the runner, which steel is accompanied by a large excess of aluminum, the latter preferably added molten. Thus, if an ingot is first poured to contain 11 tons, of which 1 /2 tons solidifies during the rimming period, there is left a core of 10 tons of molten steel. If 2 additional tons of steel are now added through the runner, making a total of 12 tons of liquid steel, then the last-added 2 tons should be accompanied by 36 lbs. of aluminum, so as to provide 3 lbs. of aluminum per ton for the 12 tons of liquid steel. In other words, an ingot is produced that consists primarily of nonaging steel that is free from blowholes and metalloid segregations and which has all the characteristics of a nonaging and, hence, fully killed low-carbon steel ingot excepting that it has a skin or very clean low-carbon steel permitting this ingot to be rolled into products such as sheets having the fine surface finish characteristics of rimmed steel but which are not subject to the latters objectionable aging phenomenon when tempered by cold working if a time period is permitted to lapse prior to its bein subjected to the deepdrawing or other severe forming operations for which the products are intended.

ingots have been produced in accordance with the present invention and processed into terne plate which was used for particularly difficult working under conditions where aging effects in the case of rimmed steel, terne plate had caused considerable trouble, the product having all the desirable characteristics of rimmed steel and being satisfactorily free from the latters agin characteristics.

It is to be understood that an ingot of the character involved by the present invention rolls to an ultimate product consisting of a core or base of nonaging steel covered by a very thin integral layer of very clean low-carbon steel providing the viously described working product with a fine finish and 800d deep-drawlns silicon contents and is cast as such in the cue oi characteristics. As is well known, a product rolled the initial pouring. Then. at the time oi treatina' t y from nonasinz steel cannot be produced the still liquid steel comprising the interior or the with the fine finish characteristic of rimmed steel.

The aluminum added to the n naains steel which is used to treat the core of the initially cast or efi'ervescing steel, may be handled in any conventional manner. However, experience has shown that probably it is best done by adding the aluminum in molten form into the runner 00nventionally used in the bottom pouring 0t ingots. the amount oi aluminum being proportioned as previously described to produce a nonaging steel.

Although low-carbon steels 0! various compositions may be used in carrying out the present invention. the steel specifically used in the pre- 01 this invention had the following ladle analysis:

Per cent Per cent Carbon .07 Sulphur .027 Manganese .37 Silicon .010 Phosphorus .009 Copper .04

The above steel. of course, is normally a rimruins of eilervescing steel in view of its carbon and ingot, 3 lbs. 0! aluminum per ton of interior steel were added as described. This resulted in the steel beina modified to the extent that it was killed and. in addition, contained metallic aluminum in an amount above that which would have i been required merely to combine with enough oxygen to effect kill na.

I claim:

1. Nonazing, i'ully killed, plain-carbon steel having a skin 01' clean, unkilled. plain-carbon steel providing the fine suriace characteristics of rimmed steel.

2. A method 01' makin: steel. comprisins bottom pouring a steel ingot oi rlmmina. plain-carbon steel; allowing an ingot skin to f rm: and. prior to solidification oi the ingot core, further bottom pouring plain-carbon steel. into the same inlot, containing sufiicient aluminum to render the inset core nonacina. fully killed. plain-carbon steel: and allowing the core to solidify.

JAMES E. LOSE.

CERTIFICA 'I'E OF CORRECTION.

' Patent No; 2,587,9 9-

October 30, 1915.

JAMES E LOSE It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1,. first column, line 55, after "evil" insert --effeci:s--; line 25, for "of effervescing" read --or effervescing page 2, first column,

' and that the said Letters Patent shouldbe read with this correction therein that the same may conform to the record of the case in the Patent Office. Signed and sealed this 12th day of February, A. 19%.

(sesii Leslie Frazer First Assistant Commissioner of Patents.

. viously described working product with a fine finish and 800d deep-drawlns silicon contents and is cast as such in the cue oi characteristics. As is well known, a product rolled the initial pouring. Then. at the time oi treatina' t y from nonasinz steel cannot be produced the still liquid steel comprising the interior or the with the fine finish characteristic of rimmed steel.

The aluminum added to the n naains steel which is used to treat the core of the initially cast or efi'ervescing steel, may be handled in any conventional manner. However, experience has shown that probably it is best done by adding the aluminum in molten form into the runner 00nventionally used in the bottom pouring 0t ingots. the amount oi aluminum being proportioned as previously described to produce a nonaging steel.

Although low-carbon steels 0! various compositions may be used in carrying out the present invention. the steel specifically used in the pre- 01 this invention had the following ladle analysis:

Per cent Per cent Carbon .07 Sulphur .027 Manganese .37 Silicon .010 Phosphorus .009 Copper .04

The above steel. of course, is normally a rimruins of eilervescing steel in view of its carbon and ingot, 3 lbs. 0! aluminum per ton of interior steel were added as described. This resulted in the steel beina modified to the extent that it was killed and. in addition, contained metallic aluminum in an amount above that which would have i been required merely to combine with enough oxygen to effect kill na.

I claim:

1. Nonazing, i'ully killed, plain-carbon steel having a skin 01' clean, unkilled. plain-carbon steel providing the fine suriace characteristics of rimmed steel.

2. A method 01' makin: steel. comprisins bottom pouring a steel ingot oi rlmmina. plain-carbon steel; allowing an ingot skin to f rm: and. prior to solidification oi the ingot core, further bottom pouring plain-carbon steel. into the same inlot, containing sufiicient aluminum to render the inset core nonacina. fully killed. plain-carbon steel: and allowing the core to solidify.

JAMES E. LOSE.

CERTIFICA 'I'E OF CORRECTION.

' Patent No; 2,587,9 9-

October 30, 1915.

JAMES E LOSE It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1,. first column, line 55, after "evil" insert --effeci:s--; line 25, for "of effervescing" read --or effervescing page 2, first column,

' and that the said Letters Patent shouldbe read with this correction therein that the same may conform to the record of the case in the Patent Office. Signed and sealed this 12th day of February, A. 19%.

(sesii Leslie Frazer First Assistant Commissioner of Patents. 

